Add Non interactive fee bumping example

[sanket1729]

Had to refactor some of the dummy_env stuff.

If I try to include change output in the default env, everything breaks and I did not want to spend time trying to fix all of tests. Instead, we create a new default with fee just for this one test case.

[apoelstra]

In 8231b95: trailing whitespace on several lines.

[apoelstra]

In 8231b95:

Looks like you're using left_pad in a couple places to widen integer types. You can just use <u64>::from or <u32>::into.

Your changes to the test environment seem fine to me.

[apoelstra]

Done reviewing 16ebe74

[sanket1729]

Looks like you're using left_pad in a couple places to widen integer types. You can just use ::from or ::into.
Your changes to the test environment seem fine to me.

Can I do it. The casting table requires me to construct a tuple (u1, u1) to cast to u2. So I will need 6 of them to cast to u64?

[apoelstra]

cc @uncomputable can you provide some guidance here? It doesn't seem right that the user has to call a jet explicitly for integer promotion.

[sanket1729]

let v2 : u64 = <u1>::into(v1);
   |                    ^^^^^^^^^^^^^^ Cannot cast values of type `u1` as values of type `u64`

[uncomputable]

f2ccc62: <u1>::into(jet::complement_1(<bool>::into(v))) should be shorter to write and cheaper in fees. The casting <T>::into is free and doesn't appear in the Simplicity target code.

Simfony should have an in-built Boolean negation function.

[uncomputable]

ab42d67: Are you using rust analyzer? clippy didn't show me these lints. I can integrate a better linker than clippy into my workflow if there is one.

[apoelstra]

@uncomputable I think that these lints showed up in a fairly recent version of nightly (maybe stable now?) and you just need to update your toolchain to see them.

[uncomputable]

Casting is possible when two Simfony types are based on the same Simplicity type. Casting is a NOP in terms of Simplicity. Integers with different bit width are different types in Simplicity, so there is no cast.

To convert u1 to u64, left_pad_low_1_64 can be called. That seems to be the cheapest and most concise way. Alternatively, a nested tuple of integers and Booleans can be cast into u64. The cast itself is free, but constructing the tuple is not.

let b: bool = true;
let x: u64 = <(u32, (u16, (u8, (u4, (u2, (u1, bool))))))>::into((0, (0, (0, (0, (0, (0, b)))))));
assert!(jet::eq_64(x, 1));

[uncomputable]

ACK ab42d67 Feel free to optimize the check_neg function.

[uncomputable]

I have code to dynamically generate witness data for most of the Simfony examples, so we can change the Elements environment without every test failing. I will make a PR when the API is ready and integrate the hotfix from this PR.

[apoelstra]

ACK ab42d67; successfully ran local tests

[sanket1729]

I am planning to post this example on delving bitcoin to get some more attention to simphony and some cool applications. Let me know if you have any objections

[uncomputable]

That's a great idea. Make sure you hit the right spelling :)